|
Lead-acid batteries are the most common type of battery in both utility and nonutility applications.
A couple of variations on the traditional design have emerged:
- Valve-regulated lead-acid (VRLA) batteries — are sealed and need no topping off with water, and so require less maintenance than regular lead-acid batteries. VRLAs are popular in distributed power applications.
- Gel-type lead-acid batteries — are filled with a gel instead of liquid, making them much less likely to spill. These are becoming popular in Europe.
How It Works
The traditional lead-acid battery is made up of plates, lead, and lead oxide immersed in a solution consisting of 35% sulfuric acid and 65% water. This solution is called "electrolyte," and causes a chemical reaction that produces electrons. Various other elements are also used to change the density, hardness, and porosity of the plates.
When you test a battery, you are measuring the amount of sulfuric acid in the electrolyte. If your reading is low, that means the chemistry that makes electrons is lacking. So where did the sulfur go? It is stuck to the battery plates and when you recharge the battery the sulfur returns to the electrolyte.
Advantages
Lead-acid batteries are widely used, are inexpensive, and have fairly well-known operating characteristics. Gel types are very robust and can take more heat and charge abuse than traditional lead-acid batteries.
Disadvantages
Careful integration with power electronics is the key to successful use of batteries for energy storage. Gel batteries are somewhat more expensive than traditional lead-acid batteries.
The suitability of a battery system to utility applications is affected by factors such as its response time, power density (the amount of power available from a battery in relation to its mass or volume), discharge rate, and life cycle costs.
Applications
Lead-acid batteries are used in automobiles, and by both utilities and electricity consumers as a backup energy source for critical electricity needs.
Utility battery storage systems allow utilities or utility customers to chemically store electrical energy for dispatch at a time when its use is more economical, strategic, or efficient.
|
